Isoparaffin alkylation process using an unsupported perfluorinated polymer catalyst

ABSTRACT

A process and catalyst for the alkylation of isoparafffins is disclosed. The catalyst is an unsupported solid perfluorinated polymer containing pendent sulfonic acid groups.

This is a division of application Ser. No. 663,897, filed Feb. 4, 1976and issued as U.S. Pat. No. 4,022,847.

BACKGROUND OF THE INVENTION

Hydrocarbon conversion and the isomerization of hydrocarbons inparticular, is of special importance to the petroleum industry. Inrecent years, with the advent of catalytic converters in automobiles andthe required use of non-leaded gasoline, a need has arisen for higheroctane number gasolines. Natural straight-run gasolines, i.e., naphthas,contain, chiefly, normal paraffins, such as normal pentane and normalhexane, which have relatively low octane numbers. It has becomeessential, therefore, to convert these low octane components to theirhigher octane counterparts. The isomerization of these hydrocarboncomponents accomplish this conversion, i.e., the isomers resulting havea much higher octane rating. Hence, the facility with which thisisomerization is accomplished has become of prime importance.

Likewise, the need for isoparaffins, benzene, xylene, and ethyl benzeneas building components in the petrochemical industry is increasing.Accordingly, the need for improved hydrocarbon conversion processes inthe petrochemical industry is also great.

One of the primary hydrocarbon conversion processes now employed is thealkylation of isoparaffins. It was thought that certain sulfonatedfluorocarbon polymers possess sufficient activity and stability to beuseful as alkylation catalysts. However, in a recent study by Kapura andGates, Sulfonated Polymers as Alkylation Catalysts, IndustrialEngineering Chemistry Product Research Development, Vol. 12, No. 1, pp.62-66 (1973), It was found that a sulfonated fluorocarbon vinyl etherpolymer was inactive in alkylating isobutane with propylene in the gasphase and in a mole ratio of 5 to 1 at 260° C. The conclusion reached inthat study was that the sulfonated fluorocarbon vinyl ether polymercatalyst was too weakly acidic to catalyze paraffin alkylation and thatthe polymer was not a useful catalyst. That study also showed that thesesame ion exchange resins were useful in the alkylation of benzene withpropylene in the vapor phase to form cumene. However, the conclusionreached by Kapura and Gates with regard to the formation of cumene wasthat the sulfonated polymer was not "a particularly useful catalyst attemperatures greater than about 150° C." Contrary to the conclusionsreached by Kapura and Gates, it has now been found that a perfluorinatedpolymer containing pendant sulfonic acid groups is a very activecatalyst in the preparation of ethylbenzene from benzene and ethylene,in the alkylation of isoparaffins, in the isomerization of normalalkanes, and in the disproportionation of toluene.

SUMMARY OF THE INVENTION

The present invention comprises an improved hydrocarbon conversionprocess which comprises contacting said hydrocarbons under hydrocarbonconverting conditions with an unsupported perfluorinated polymercatalyst containing a repeating structure selected from the groupconsisting of: ##STR1## where n is 0, 1 or 2; R is a radical selectedfrom the group consisting of fluorine and perfluoroalkyl radicals havingfrom 1 to 10 carbon atoms; and X is selected from the group consistingof:

    [O(CF.sub.2).sub.m ], [OCF.sub.2 CFY] or [OCFYCF.sub.2 ]

where m is an integer from 2 to 10 and Y is a radical selected from theclass consisting of fluorine and the trifluoromethyl radical.

DETAILED DESCRIPTION OF THE INVENTION

A. The Catalyst

The catalyst employed in the present invention is a solid at reactionconditions. The catalyst broadly comprises a perfluorinated polymerhaving acid groups in the amount of about 0.01 to 5 mequiv/gramcatalyst. Preferably, the polymer contains about 0.05 to 2 mequiv/gramof catalyst.

In a specific embodiment, the polymer catalyst contains a repeatingstructure selected from the group consisting of: ##STR2## where n is 0,1 or 2; R is a radical selected from the group consisting of fluorineand perfluoroalkyl radicals having from 1 to 10 carbon atoms; and X isselected from the group consisting of:

    [O(CF.sub.2).sub.m ], [OCF.sub.2 CFY] or [OCFYCF.sub.2 ]

where m is an integer from 2 to 10 and Y is a radical selected from theclass consisting of fluorine and the trifluoromethyl radical. In apreferred embodiment, n is 1 or 2, Y is a trifluoromethyl radical, R isfluorine, and m is 2. Catalysts of the above-noted structure typicallyhave a molecular weight of between about 1,000 and 500,000 daltons.

Polymer catalysts of the above-noted structure can be prepared invarious ways. One method, disclosed in Connolly et al, U.S. Pat. No.3,282,875 and Cavanaugh et al, U.S. Pat. No. 3,882,093, comprisespolymerizing vinyl compounds of the formula:

    CF═CF[X].sub.n OCF.sub.2 CFRSO.sub.3 H                 III

or ##STR3## in a perfluorocarbon solvent using a perfluorinated freeradical initiator. Since the vinyl ethers are liquid at reactionconditions, it is further possible to polymerize and copolymerize thevinyl ethers in bulk without the use of a solvent. Polymerizationtemperatures vary from -50° to +200° C. depending on the initiator used.Pressure is not critical and is generally employed to control the ratioof the gaseous comonomer to the fluorocarbon vinyl ether. Suitablefluorocarbon solvents are known in the art and are generallyperfluoroalkanes or perfluorocycloalkanes, such as perfluoroheptane orperfluorodimethylcyclobutane. Similarly, perfluorinated initiators areknown in the art and include perfluoroperoxides and nitrogen fluorides.It is also possible to polymerize the vinyl ethers of structure III orIV in an aqueous medium using a peroxide or a redox initiator. Thepolymerization methods employed correspond to those established in theart for the polymerization of tetrafluoroethylene in aqueous media.

It is also possible to prepare catalysts for the present invention bycopolymerizing the vinyl ethers of structure III or IV withperfluoroethylene and/or perfluoro-alpha-olefins. A preferred copolymerprepared by polymerizing perfluoroethylene with a perfluorovinyl ethercontaining attached sulfonic acid groups would have the followingstructure: ##STR4## wherein n=1 or 2 and the ratio of x over y variesfrom about 2 to about 50. The polymer of structure V is availablecommercially under the tradename of NAFION® resin. Catalysts of theabove-noted structure V offer the advantages of high concentrations ofaccessible acid groups in a solid phase.

The invention is further defined with reference to a variety ofparticular hydrocarbon conversion processes.

B. Alkylation of Isoparaffins

The catalytic alkylation of paraffins involves the addition of anisoparaffin containing a tertiary hydrogen to an olefin. The process isextensively used by the petroleum industry to prepare highly branchedparaffins mainly in the C₇ to C₉ range, which are high quality fuels forignition engines. The overall process as to chemistry is a composite ofcomplex reactions, and consequently a rigorous control of operatingconditions and of catalyst is needed to assure predictable results.

Acid catalyzed hydrocarbon conversion processes comprising contacting analkane with an olefin are well known. The reactants are generallycontacted in the liquid phase and within a broad temperature range ofabout -100° F. to about 100° F. with an acid catalyst such as, forexample, sulfuric acid, fluorosulfuric acid or a halogen acid, such ashydrofluoric acid. Typical alkylation processes are disclosed in U.S.Pat. No. 2,313,103, U.S. Pat. No. 2,344,469, U.S. Pat. No. 3,864,423 andBritish Pat. No. 537,589. Catalyst moderators, such as water and lowermonoethers as disclosed in U.S. Pat. No. 3,887,635, are often employedto improve the selectivity of the catalyst.

The catalysts employed in the above-noted references are liquidcatalysts. Therefore, the process equipment must be necessarily complex.The reaction zone typically contains elaborate hardware to ensureinitmate mixing of catalyst and reactions. In addition, a separationchamber is required to separate the catalyst from the hydrocarbonproduct. Further, since the reaction typically takes place at lower thanembient temperature, refrigeration facilities are also a necessary partof the process.

One means to improve the alkylation process would be to employ a solidcatalyst instead of a liquid catalyst. However, conventional solid acidcatalysts, such as zeolites, are not very stable in their catalyticactivity. For example, during isobutane/butene-2 alkylation, zeolitesundergo catastrophic decline in activity in 4 to 6 hours. Likewise,other solid alkylation catalysts, such an HF antimony pentafluoridecatalyst as disclosed in U.S. Pat. No. 3,852,371, are not commerciallystable catalysts.

In the present invention, a C₄ to C₆ isoparaffin containing a tertiaryhydrocarbon or a hydrocarbon stream containing such isoparaffins iscontacted with a C₃ to C₅ monoolefin, mixtures thereof, or hydrocarbonstreams containing such olefins, in the liquid phase and at atemperature of between about 80° C. and about 225° C. in the presence ofthe catalyst of the instant invention.

The present invention has a distinct advantage over the typicalalkylation process in that the catalyst is a solid catalyst therebyeliminating many of the mixing, settling, separation, and neutralizationproblems associated with catalysts such as sulfuric acid, hydrofluoricacid, or fluoromethane sulfuric acid. The present catalyst is alsosuperior to the other solid catalysts such as zeolites in that thepresent catalyst is very stable under reaction conditions. For example,catalyst runs with the instant catalyst of over 200 hours have beenachieved with an appreciable decline in catalyst activity.

Further, contrary to prior investigations, the present catalyst is veryactive in the alkylation reaction resulting in over 90% conversion ofthe olefin and over 80% C₈ selectivity. In addition, thetrimethylpentane selectivity (basis C₈ H₁₈) of the present catalyst isover 75%.

The olefin feed for the present invention contains olefins selected fromthe group consisting of C₃ to C₅ monoolefins and mixtures thereof.Examples of suitable olefins include propylene, isobutylene, butene-1,and butene-2, trimethylethylene, the isomeric amylenes and mixturesthereof. In actual commercial use, however, these olefins will containother hydrocarbons. The process of the instant invention contemplatesthe use of various refinery cuts as feedstocks. Thus, C₃, C₄ and/or C₅olefin cuts from thermal and/or catalytic cracking units; field butaneswhich have been subjected to prior isomerization and partialdehydrogenation treatment; refinery stabilizer bottoms; spent gases;normally liquid products from sulfuric acid or phosphoric acid catalyzedpolymerization and copolymerization processes; and products, normallyliquid in character, from thermal and/or catalytic cracking units, areall excellent feedstocks for the present process.

The isoparaffin feed for the present invention comprises C₄ to C₆isoparaffins containing tertiary hydrocarbon substituents, mixturesthereof, and hydrocarbon streams containing such components. A preferredisoparaffin is isobutane.

In order to prevent polymerization of the olefin, a large excess ofisoparaffin is used. The weight ratio of isoparaffin to olefin variesfrom about 5:1 to about 1000:1, preferably about 20:1 to about 60:1. Ithas been found that when the isobutane to butene ratio is increased from10:1 to 40:1, the C₈ selectivity and the total yield of greater than orequal to C₅ products are significantly increased while the yield of C₁₁-C₁₂ and C₁₄ -C₁₆ products are decreased.

The process may be carried out either as a batch or continuous type ofoperation, although it is preferred to carry out the processcontinuously. It has been generally established that in alkylationprocesses, the more intimate the contact between the feedstock and thecatalyst, the better the yield of saturated product obtained. With thisin mind, the present process, when operated as a batch operation, ischaracterized by the use of vigorous mechanical stirring or shaking ofthe reactants and catalyst.

When employing a continuous process, the feedstreams may be contactedwith the catalyst in any suitable reactor. In one embodiment, thecatalyst is packed in a vertical, tubular reactor bed with inertsupports, such as ceramic balls or silicon carbide, above and below thecatalyst to prevent entrainment of the solid catalyst. In a furtherembodiment, the catalyst is mixed with an inert material, such asquartz, and loaded in the reactor so as to improve the fluid dynamics ofthe system. The flow of the reactant feed stream may be upflow ordownflow, with an upflow arrangement being preferred to ensure liquidphase alkylation.

Reaction temperature is varied between about 80° C. and about 225° C.depending upon the type of products desired. The reaction temperaturemust be kept below about 225° C. due to the lack of stability of thecatalyst at temperatures of over 250° C. A preferred temperature rangeis between about 80° C. and about 130° C. In general, the activity ofthe catalyst is greater at the higher temperatures. That is, astemperature increases, the conversion of olefin increases.

In general, the pressure in the alkylation reaction zone is maintainedto keep the reactants in the liquid phase, and accordingly, will varywith the reactants employed and the reaction temperatures. Typicalreaction zone pressure varies from about 10 psig to about 2,000 psig.

The weight hourly space velocity effectively measures the catalystconcentration employed, and hence also measures the relative activity ofthe catalyst. Weight hourly space velocity (WHSV) is defined as theweight per hour of olefin feed divided by the weight of catalystemployed. For non-supported catalyst, the WHSV varies between about 0.05and about 1.0, preferably about 0.15 and about 0.5.

In a preferred embodiment, a gas stream is introduced into the reactoralong with the olefin and isoparaffin feed streams. Typically, the gasis an inert gas such as nitrogen. However, it has been found that whenthe gas stream also contains hydrogen, the total yield of C₅ or greaterproducts is increased without significantly increasing the n-butaneselectivity or changing the trimethylpentane selectivity. The effect ofincluding this gas stream in the alkylation reaction is to improve thepercentage of C₈ H₁₈ in the C₈ product, which improvement most likelyoccurs via hydride transfer from hydrogen to an intermediate C₈carbonium ion to give a C₈ H₁₈ alkane.

The reaction products obtained are highly branched paraffins, mainly inthe C₅ to C₁₂ range. The butenes produce mainly C₈ hydrocarbons,principally dimethylhexanes and trimethylpentanes, while isobutyleneresults in mainly trimethylpentanes. It is not necessary to neutralizethe reaction products of the present invention, since little, if any, ofthe sulfonic acid groups on the catalyst are removed during thereaction.

The principal use of the alkylate produced according to the presentinvention is in the blending of motor gasoline. Alkylate is a preferredgasoline blending component because of its high octane number, whichnumber is enhanced by the presence of high concentrations of C₈hydrocarbons. Trimethylpentane is a particularly valuable alkylatecomponent.

The invention is further illustrated by means of the followingIllustrative Embodiments which are given for the purpose of illustrationonly, and the invention is not to be regarded as limited to any of thespecific materials or conditions recited therein.

In the Illustrative Embodiments, the reactor employed was a 17-inchstainless steel tube equipped with both a liquid feed upflow inlet and anitrogen inlet. The catalyst bed occupied about 10 inches in the centerof the reactor; and on either side of the catalyst bed were packed about10 grams of carborundum chips. The catalyst bed was initially chargedwith liquified isobutane at a flow rate of 10-20 milliliters per hourafter the reactor was heated to 80°-120° C. Once the reactor wascompletely flooded with isobutane, the mixture of olefin and isoparaffinwere charged to the reactor. In all cases, the olefin employed was2-butene and the isoparaffin employed was isobutane.

In the Illustrative Embodiments, the reactants were introduced in anupflow manner. Pressure in all cases was kept at 500 psig to maintain aliquid phase. Except as noted, a 100% nitrogen gas was added at a rateof 0.3 liters per hour.

The products were recovered at periodic intervals and analyzed by gaschromatography. The percentage of alkenes in the C₈ fraction weredetermined by washing the fraction with 96% sulfuric acid to remove thealkenes.

In the Illustrative Embodiments, the catalyst concentration is measuredby weight hourly space velocity (WHSV, hr⁻¹) which is defined as theweight of the 2-butene feed per hour divided by the weight of catalystemployed. The total yield of greater than or equal to C₅ products isbased on the weight of butene converted. Further, since2,2,5-trimethylhexane is the only significant C₉ product formed and hasa high octane number, it is included in the C₈ H₁₈ fraction as reported.

Illustrative Embodiment Ia

The catalyst for Illustrative Embodiment Ia was prepared by grindingNafion XR granules with a blender to 150 micrometer or less particlesize. The ground material was then treated twice with 30% sulfuric acidto convert the material from a potassium (K⁺) form to the H⁺ form. Thetreated material was collected by filtration, washed with distilledwater until the washings were neutral, and then dried at 100° C. and 3mm pressure for 16 hours. The resulting catalyst contained about 0.85milliequivalents of acid per gram of catalyst. The structure for theresulting catalyst is exemplified by the following repeating structurewhere n=1 or 2 and the ratio of x over y varies from between 2 to about50: ##STR5##

In Illustrative Embodiment Ia, the catalyst bed comprised 2.5 grams ofcatalyst plus 7.5 grams of quartz particles. The isobutane to butene-2ratio was maintained at about 10 to 1, whereas the WHSV and temperaturewere varied as indicated. The total length of the run lasted over 90hours, and the results are presented below in Tables 1a, 2a and 3a.

                                      Table 1a                                    __________________________________________________________________________    Time, hrs    3  5  7  9  11 13 15 16 18 19 20 22                              WHSV, hr     0.4                                                                              0.4                                                                              0.4                                                                              0.4                                                                              0.4                                                                              0.66                                                                             0.66                                                                             0.66                                                                             0.66                                                                             0.66                                                                             0.66                                                                             0.66                            Temperature, °C.                                                                    100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100                                                                              100                             Butene Conversion, %                                                                       97 97 97 98 99 96 96 96 95 95 95 96                              Total Yield ≧C.sub.5 's, % w                                                        150                                                                              147                                                                              146                                                                              146                                                                              147                                                                              145                                                                              146                                                                              146                                                                              146                                                                              146                                                                              145                                                                              146                             Products, % w                                                                  C.sub.5 --C.sub.7                                                                         3  3  2  2  2.5                                                                              2  2  2  1.5                                                                              2  2  1.5                              C.sub.8 --C.sub.9                                                                         65 65 65 65 64 68 68 70 71 70 71 71                               C.sub.11 --C.sub.12                                                                       20 20 22 22 20 20 19 17 17 17 16 19                               C.sub.14 --C.sub.16                                                                       12 12 11 11 13.5                                                                             10 11 11 11 11 11 9.5                             Composition of C.sub.8, %                                                      C.sub.8 H.sub.18                                                                          81 70 70 70 73 66 67 65 65 65 64 64                               C.sub.8 H.sub.16                                                                          19 30 30 30 27 34 33 35 35 35 36 36                              Composition of C.sub.8 H.sub.18, %                                             Trimethylpentanes                                                                         75 75 70 71 63 67 70 71 74 66 66 67                               Dimethylhexanes                                                                           18 18 19 20 24 20 21 20 19 24 22 23                               Methylheptanes                                                                            4  4  6  5  6  6  4  4  4  5  6  5                                2,2,5-Trimethylhexane                                                                     4  4  5  5  7  7  5  5  3  5  6  5                               __________________________________________________________________________

                                      Table 2a                                    __________________________________________________________________________    Time, Hr.    24 26 28 30 32 33 34 36 38 39.5                                                                             42.5                                                                             44.5                                                                             46                           WHSV, hr..sup.-1                                                                           0.66                                                                             0.66                                                                             0.66                                                                             0.66                                                                             0.66                                                                             0.66                                                                             0.66                                                                             0.66                                                                             0.66                                                                             0.66                                                                             0.66                                                                             0.66                                                                             0.66                         Temperature, °C.                                                                    90 90 90 90 90 90 90 90 90 90 90 90 90                           Butene, Conversion, %                                                                      86 85 85 87 85 85 84 87 87 88 87 85 88                           Total Yield ≧C.sub.5 's                                                             142                                                                              140                                                                              140                                                                              140                                                                              139                                                                              139                                                                              140                                                                              143                                                                              140                                                                              142                                                                              138                                                                              139                                                                              141                          Products, % w                                                                  C.sub.5 --C.sub.7                                                                         3  2  1  2  1  1  2  1  1  1  2  1  1                             C.sub.8 --C.sub.9                                                                         74 74 73 74 73 74 73 74 74 75 74 73 74                            C.sub.11 --C.sub.12                                                                       14 16 17 16 15 16 14 16 16 14 16 17 15                            C.sub.14 --C.sub.16                                                                       10 9  9  9  11 9  11 9  9  10 8  9  10                           Composition of C.sub.8, %                                                      C.sub.8 H.sub.18                                                                          56 58 56 58 56 57 60 58 57 56 57 57 58                            C.sub.8 H.sub.16                                                                          44 42 44 42 44 43 40 42 43 44 43 43 43                           Composition of C.sub.8 H.sub.18, %                                             Trimethylpentanes                                                                         75 74 75 75 74 75 74 73 75 73 74 75 75                            Dimethylhexanes                                                                           18 18 17 17 18 19 17 19 17 19 17 19 18                            Methylheptanes                                                                            3  4  4  4  4  4  5  4  5  5  5  4  4                            2,3,5-Trimethylhexane                                                                      4  4  4  4  4  2  4  5  3  3  4  2  3                            __________________________________________________________________________

                                      Table 3a                                    __________________________________________________________________________    Time, hrs.   50 52 56 58 60 66  70 72 90                                      Temperature, °C.                                                                    90 90 80 80 80 80  90 90 90                                      WHSV, hr.sup.-1                                                                            0.33                                                                             0.33                                                                             0.33                                                                             0.33                                                                             0.33                                                                             0.33                                                                              0.33                                                                             0.33                                                                             0.33                                    Butene Conversion, %                                                                       95 95 76 73 70 68-72                                                                             91 94 95                                      Total Yield≧C.sub.5 's                                                                 140                                                                              139                                                                              138                                                                              138                                                                              138 140                                                                              141                                                                              141                                     Products, % w                                                                  C.sub.5 --C.sub.7                                                                            1.5                                                                              <1 <1 <1 <1  1  1.5                                                                              1.6                                      C.sub.8 --C.sub.9                                                                            68 78 78 80 81  68 68 70                                       C.sub.11 --C.sub.12                                                                          18 13 15 13 11  19 19 17                                       C.sub.14 --C.sub.16                                                                          13 9  6  7  7   12 11.5                                                                             12                                      Composition of C.sub.8, %                                                      C.sub.8 H.sub.18                                                                             60 50 49 48 50  58 58 56                                       C.sub.8 H.sub.16                                                                             40 50 51 52 50  42 42 44                                      Composition of C.sub.8 H.sub.18, %                                             Trimethylpentanes                                                                            75 83 80 80 80  75 75 74                                       Dimethylhexanes                                                                              18 12 14 14 15  19 18 17                                       Methylheptanes 4  3  3  3  3   4  4  5                                        2.2.5-Trimethylhexane                                                                        3  2  3  3  2   2  3  4                                       __________________________________________________________________________

Illustrative Embodiment IIa

Illustrative Embodiment IIa was conducted in a similar manner toIllustrative Embodiment Ia except that the ratio of isobutane tobutene-2 was increased to 40:1. At this higher ratio, both theselectivity and conversion were substantially higher than that observedat a 10:1 ratio. The results are presented below in Table 4a.

                                      Table 4a                                    __________________________________________________________________________    Time, hours  4  22 24.5                                                                             46.5                                                                             53.5                                                                             60 82                                             Temperature, °C.                                                                    100                                                                              100                                                                              110                                                                              110                                                                              110                                                                              110                                                                              110                                            WHSV, hr.sup.-1                                                                            0.18                                                                             0.09                                                                             0.36                                                                             0.09                                                                             0.18                                                                             0.36                                                                             0.36                                           Butene Conversion, %                                                                       82 93 82 >98                                                                              92 86 87                                             Total Yield≧C.sub.5 's                                                              172                                                                              172                                                                              160                                                                              163                                                                              168                                                                              158                                                                              159                                            Products, % w                                                                  C.sub.5 --C.sub.7                                                                         3  4  3  7.5                                                                              4.5                                                                              3  2.5                                             C.sub.8 --C.sub.9                                                                         85 85 85 75 83 84 86                                              C.sub.11 --C.sub.12                                                                       8  7  10 14 10 11.5                                                                             10                                              C.sub.14 --C.sub.16                                                                       4  4  2.5                                                                              3.5                                                                              2.5                                                                              2  2.5                                            Composition of C.sub.8, %                                                      C.sub.8 H.sub.18                                                                          85 85 70 84 82 69 68                                              C.sub.8 H.sub.16                                                                          15 15 30 16 18 31 32                                             Composition of C.sub.8 H.sub.18, %                                             Trimethylpentanes                                                                         76 67 75 60 74 75 75                                              Dimethylhexanes                                                                           15 18 18 26 17 17 18                                              Methylheptanes                                                                            3  5  2  4  3  2  2                                              2,2,5-Trimethylhexane                                                                      6  10 5  10 6  6  5                                              __________________________________________________________________________

Illustrative Embodiment IIIa

In Illustrative Embodiment IIIa the catalyst of Illustrative EmbodimentIa was employed in a catalyst loading of 1.25 grams catalyst and 8.75grams quartz. The ratio of isobutane to butene-2 was 40:1, and thepressure was maintained at 500 psig. The results are presented below inTable 5a. As can be seen, the higher WHSV results in an improvedtrimethylpentane selectivity.

                  Table 5a                                                        ______________________________________                                        Time, Hours    4      23.5   27.5 46.5 65   70                                WHSV, hr.sup.-1                                                                              0.3    0.3    0.6  0.6  0.3  0.6                               Temperature, °C.                                                                      110    110    110  110  110  120                               Butene Conv., %                                                                              70     84     68   66   83   83                                Total Yield≧C.sub.5 's                                                                160    159    155  154  159  153                               Products, % w                                                                  C.sub.5 --C.sub.7                                                                           5      4      3    3    3    3                                  C.sub.8 --C.sub.9                                                                           90     84     88   87   83   84                                 C.sub.11 --C.sub.12                                                                         5      9      8    9    11   10                                 C.sub.14 --C.sub.16                                                                         --     3      2    2    3    3                                 Composition of C.sub.8, %                                                      C.sub.8 H.sub.18                                                                            67     70     62   62   71   62                                 C.sub.8 H.sub.16                                                                            33     30     38   38   29   38                                Composition of C.sub.8 H.sub.18, %                                             Trimethylpentanes                                                                           75     76     81   80   74   79                                 Dimethylhexanes                                                                             17     16     13   13   18   14                                 Methylheptanes                                                                              2      2      2    2    2    2                                  2,2,5-Trimethylhexane                                                                       6      6      4    5    7    5                                 ______________________________________                                    

Illustrative Embodiment IVa

Illustrative Embodiment IVa was conducted with similar conditions toIllustrative Embodiment IIIa, except that a gas was introduced near thebottom of the reactor. The composition of this gas was varied from 100%nitrogen to 5% hydrogen/95% nitrogen back to 100% nitrogen and then to100% hydrogen. The results and other conditions are presented below inTable 6a.

                                      Table 6a                                    __________________________________________________________________________    Time, Hours  20   46   52  78  97   119  125  175                             Nature of Gas Phase                                                                        100% N.sub.2                                                                       100% N.sub.2                                                                       5% H.sub.2                                                                        5% H.sub.2                                                                        100% N.sub.2                                                                       100% N.sub.2                                                                       100% H.sub.2                                                                       100% H.sub.2                    Temperature °C.                                                                     110  120  120 120 110  120  120  120                             WHSV, hr.sup.-1                                                                            0.18 0.30 0.30                                                                              0.30                                                                              0.18 0.30 0.30 0.30                            Butene Conv., %                                                                            80   84   85  85  80   80   82   85                              Total Yield≧C.sub.5 's                                                              168  159  164 164 163  159  164  165                             Products, % w                                                                  C.sub.5 --C.sub.7                                                                         4    4    4   4   4    4    4    5                                C.sub.8 --C.sub.9                                                                         87   85   86  86  86   85   86   85                               C.sub.11 --C.sub.12                                                                       7    8    8   8   8.5  9    8    8                                C.sub.14 --C.sub.16                                                                       2    3    2   2   2    2    2    2                               Composition of C.sub.8, %                                                      C.sub.8 H.sub.18                                                                          78   69   74  74  73   69   74   75                               C.sub.8 H.sub.16                                                                          22   31   27  26  27   31   26   26                              Composition of C.sub.8 H.sub.18, %                                             Trimethylpentanes                                                                         73   77   75  75  72   75   74   73                               Dimethylhexanes                                                                           20   17   17  17  20   17   18   18                               Methylheptanes                                                                            2    2    3   3   3    3    3    3                                2,2,5-Trimethylhexane                                                                     5    4    5   5   5    5    5    6                               __________________________________________________________________________

What is claimed is:
 1. A liquid phase alkylation process which comprisescontacting a C₄ to C₆ isoparaffin or mixtures thereof with an olefinselected from the group consisting of C₃ to C₅ monoolefins or mixturesthereof at a reaction temperature of between about 80° C. and about 225°C. in the presence of an unsupported solid perfluorinated polymercatalyst wherein said catalyst contains a repeating structure selectedfrom the group of: ##STR6## where n is 0, 1 or 2; R is a radicalselected from the group consisting of fluorine and perfluoroalkylradicals having from 1 to 10 carbon atoms; and X is selected from thegroup consisting of:

    [O(CF.sub.2).sub.m ], [OCF.sub.2 CFY] or [OCFYCF.sub.2 ]

where m is an integer from 2 to 10 and Y is a radical selected from theclass consisting of fluorine and the trifluoromethyl radical.
 2. Aprocess according to claim 1 wherein the weight ratio of saidisoparaffin to said olefin varies from about 5:1 to about 1000:1.
 3. Aprocess according to claim 1 wherein the weight ratio of isoparaffin toolefin varies from about 20:1 to about 60:1 and the reaction temperatureis from about 80° C. to about 130° C.
 4. A process according to claim 1wherein the weight hourly space velocity, defined as the weight per hourof olefin divided by the weight of catalyst employed, varies frombetween about 0.05 to about 1.0 hr⁻¹.
 5. A liquid phase alkylationprocess which comprises contacting a C₄ to C₆ isoparaffin or mixturesthereof with an olefin selected from the group consisting of C₃ to C₅monoolefins or mixtures thereof at a reaction temperature of betweenabout 80° C. and about 225° C. and with a catalyst comprising aperfluorinated copolymer of a perfluorovinyl ether andtetrafluoroethylene containing pendant sulfonic acid groups.